GUIControlsAction.cs

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

[Script(ScriptRole.Client)]
public class GUIControlsAction : MonoBehaviour
{
    public ControlsAction GoverningAction;

    public bool Enabled
    {
        get
        {
            return _enabled;
        }

        private set
        {
            if (_enabled == value)
                return;

            _enabled = value;
            if (_enabled)
            {
                for (int i = 0; i < _graphics.Length; i++)
                    _graphics[i].CrossFadeAlpha(1.0f, 0.1f, true);
            }
            else
            {
                for (int i = 0; i < _graphics.Length; i++)
                    _graphics[i].CrossFadeAlpha(0.5f, 0.1f, true);
            }
        }
    }

    Text _textElement;
    MaskableGraphic[] _graphics;
    bool _enabled = true;

    void Awake()
    {
        _textElement = GetComponentInChildren<Text>();
        _graphics = GetComponentsInChildren<MaskableGraphic>();
    }

    void Update()
    {
        _textElement.text = Controls.GetActionCaption(GoverningAction);
        Enabled = _textElement.text != "" && Controls.IsActionEnabled(GoverningAction);
    }
}